Me, too. I was just sharing an interesting anecdote. At least, interesting to me. It’s what made Footloose seem so ridiculous to me.
Widows and widowers can get married in the Church.
Lutheran Church
Premarital sex–no, but not one of the biggies.
Marrying a divorcee?–This may have been liberalized (I hope), or may vary by synod. If one is divorced, it has to be due to adultery to remarry in the church.
Number of partners–can remarry as soon as the spouse is cold in the ground. I do think there is social pressure to sit back, mourn, and reflect. Quick remarriages after widowhood are rare.
Many religions (or some proponents of a particular set of techings from them) frown on the idea of having fun. If it feels good, if it’s enjoyable, if you are having a good time, if it takes you away from solemn and somber stuff like hard work and devout worship - then it must be bad, must be the devil’s work, must be avoided. And… what’s more fun than sex? (…rhetorical question…! )
Most societies seem to have flapped back and forth between the tolerant and the “puritan” over time.
Premarital sex, or sex outside of marriage in general, ITGOD (In The Good Old Days) was also a problem because someone had to support the children.
I’m surprised nobody has mentioned “annullment”. There was a joke in Italy ITGOD that “there is no divorce in Italy and only the catholics can get it”. It has always been that people wanted out of a marriage (Henry VIII) and without divorce, the Catholic Church heirachy dreamed up annullments. With the right connections, you could get a document saying your marriage really did not count. Then you could proceed with your next, real first marriage in the Catholic church.
I hear one sect of Christianity has a “wide” stance on sex. 
IIRC - There was some senator who had a wide stance…